
public class DataStack {
	int n;
	double [] a;
	int top = -1;
	public DataStack(int m) {
		this.n=m;
	}
	void getStack() {
		a = new double[n];
	}
	void push(double data) {
		a[++top]=data;
	}
	double pop() {
		return a[top--];
	}
}
